New aqueous two-phase system based on cashew-nut tree gum and poly(ethylene glycol)

The characterisation of a new system based on cashew-nut tree gum, a branch ed acidic heteropolysaccharide found in Brazil, and poly(ethylene glycol) ( PEG) was studied. Phase diagrams are provided for the PEG-cashew-nut tree g um system. The influence of PEG molecular mass, tie-line length and pH on b ovine serum albumin (BSA) partition was investigated. Protein partition coe fficient was little influenced by changing PEG molecular mass. Increasing t he tie-line length decreased the partition. Increasing the pH also raised t he BSA partition coefficient. It is shown that systems formed by PEG and ca shew-nut tree gum may be considered as an interesting alternative for use i n protein purification. (C) 2000 Elsevier Science B.V. All rights reserved.